Final answer:
We cannot determine if the two sub-circuits are in series or parallel without a diagram. It is also possible that they cannot be broken down into series and parallel combinations. So, the correct answer is (e) Impossible to determine.
Step-by-step explanation:
When determining if two sub-circuits are in series or parallel, we need to compare how the current flows through the components.
In a series configuration, the same current must pass sequentially through the components. In a parallel configuration, all the components are connected at both ends, and each component has the same potential drop across it.
Without a diagram of the two sub-circuits, it is impossible to determine if they are in series or parallel, both, neither, or if they cannot be broken down into series and parallel combinations.
Thus, the correct answer is (e) Impossible to determine.